Integration also has consequences for U.S. efforts to stem the spread of nuclear weapons. A doctrine of integration would attempt to integrate both North Korea and Iran into the non-proliferation system. Sanctions, isolation and efforts aimed at regime change would give way in the first instance to political and economic incentives; China, Europe and others would be integrated fully into the diplomatic effort. Integration has the potential to be a bold, transforming strategy by which the United States can shape the next era of history. It is an optimistic prospect, but, after all, no more ambitious than that of, say, someone writing amid World War II of a Europe in which Franco-German friendship is the cornerstone, or of someone writing half a century ago of a post-Cold War, post-Soviet world in which markets and democracies are more the world's rule than an exception. An integrated world can, with American guidance, become an achievable reality.

There is a precedent for trying to bring about a world in which the leading states of the day do often act as partners. In the early 19th century, the major powers of the era met in Vienna and subsequently in other cities to develop understandings--rules of the road, in today's parlance--about the conduct of international relations. The goal was to devise "international agreement about the nature of workable arrangements and about the permissible aims and methods of foreign policy."2 While more modest than that, the resulting "Concert of Europe" helped to keep relative peace for several decades among the great powers--Austria, Britain, France, Prussia and Russia--then at the heart of the European state system. The arrangements were never institutionalized, much less codified as some form of world government; rather, what emerged were a set of understandings and a commitment to consult in order to avoid the sort of major power conflict Europe had just experienced.

This period following the Congress of Vienna is not the only example of coordination among the major powers of the day. More recently, the Cold War was kept "cold" by a series of implicit or informal understandings between the United States and the Soviet Union. Each avoided any direct armed intervention against the other on the grounds that escalation to nuclear war was all too possible. In addition, it was acceptable to provide military assistance to an ally or client, but not to the point of overwhelming the ally or client of the other. The most dangerous moments of the Cold War came when such "rules" were violated or came close to being violated.

Rules of the road are just as necessary today. What is needed, though, are not simply "negative" understandings among the major powers that constrain competition, but "positive" commitments about how to work together to meet pressing challenges. The challenge is not simply to erect an international society with commonly accepted restraints but to fashion coalitions and institutions that promote certain objectives sought by the United States and embraced by others.

Efforts to bring about such arrangements would not have to start from scratch. A considerable degree of integration already exists. There is, for example, near universal support for the right of self-defense, the concept that a state can respond militarily if attacked. This principle also provides an opening for those who would come to the aid of a state that has been attacked. The principle even extends to the right of pre-emptive (not to be confused with preventive) attacks, the acceptability of acting against a would-be aggressor on receipt of intelligence or a warning that indicates with extremely high certainty that a hostile attack is imminent. There are as well laws of war that specify what governments are obligated to do to safeguard the rights of combatants and noncombatants alike.

There are elements of consensus in the political realm, including a number of international conventions supporting human rights and democracy and opposing slavery, torture and genocide. Technical arrangements abound, from aviation safety and communications standards to rules affecting agricultural and health policies. Environmental agreements ban persistent organic pollutants and protect the ozone layer. And integration is arguably most advanced in the realm of trade and international economic arrangements more generally, where rules and institutions are common, most notably the World Trade Organization.

The challenge is to expand cooperation where it exists and to extend it to new areas. What, then, would a more integrated world look like? At a minimum, it would be one in which governments would not be free to commit genocide (or allow it to take place) and in which the international community could intervene in one form or another to protect the population and, if need be, remove the government from power. All or most governments would sign on to the norm that force could not be used in an intentional manner against civilians for political purposes and that they would take action against any entity that carried out terrorism or in any way supported those who did. The major powers (China, Russia, Japan, India and the eu, in addition to the United States) would agree that countries would be provided access to enriched uranium and plutonium for peaceful purposes--but denied possession of either, lest it be diverted for military purposes. The WTO would be extended to cover virtually all aspects of manufacturing and services; tariffs, quotas and subsidies would be eliminated.

Cooperation could be extended to other domains, including new arrangements for dealing with disease or poverty or global climate change. What will be required is a process for agreeing on the basic rules or objectives that would define order in this era and for determining what is to be done in those specific situations where the rules are violated. Nothing will be more important than regular consultations among the major powers. But no amount of advance consultation can ensure agreement in particular circumstances. There needs to be a commitment by the United States and others to seek the broadest possible international agreement before acting, particularly before using military force. The United Nations Security Council, its many limitations notwithstanding, is one place to try to gain multilateral backing. But it is not the only forum that offers international legitimacy and support, and if there is no chance of gaining consensus there, the United States should turn to NATO, other regional organizations, the G-8 (or, better yet, an expanded G-10 that includes India and China), or more narrowly constructed contact groups and coalitions of the willing.

The need for a pragmatic case-by-case approach is unavoidable. It is important to give the diplomatic process a fair chance and allow ample time for consensus to emerge at the UN. Consultations must be genuine and not simply an effort to insist on an already determined policy. A decision to opt out of formal multilateralism should only be made when there is an urgent need to act; the case must also be of sufficient weight or seriousness to justify acting. This is especially true when the intervention is military in nature. Preventive (as opposed to pre-emptive) uses of military force should remain a rare exception. Whenever the United States elects to go its own way, it should go to great lengths to explain itself, in private as well as in public, with as many other governments in tow as possible. It is important that there be no unique benefit, such as special access to oil, contracts for firms or military bases, that accrues to the United States or the country in question lest the intervention be seen as something other than one born of principle or necessity. And any time the United States decides to act without UN blessing it should then return as soon as possible to the formal diplomatic fold, undertaking subsequent actions with the greatest possible global or regional involvement. It is important to keep in mind that while the United States does not need the world's permission to act, it does need the world's support to succeed.

Gaining international support (or avoiding significant opposition) will also require that the United States take the concerns of the other major powers into account. In the case of China, for example, this translates into resisting Taiwan's movement toward independence, or working to see that other states in northeast Asia do not develop nuclear weapons so long as China does all it can to see that North Korea gives up its program. It requires accepting India's nuclear weapons program, recognizing Japan's re-emergence as not only an economic but also a political and military power, and supporting the desire of both India and Japan to gain a seat on the UN Security Council. It calls for welcoming a stronger European Union. It can mean not making a priority of the democratic shortcomings of either China or Russia. The reward to the United States for such adjustments to its policies would be that another power would be more inclined to participate in a more integrated world or, on those occasions it disagrees, at least not work actively against what the United States seeks to accomplish.